Field of the Invention
This invention relates to a food shaping apparatus, and more particularly to an apparatus for automatically successively shaping a rice food such as oval-shaped sushi, a rice ball or the like which has been conventionally hand-shaped.
The term "oval-shaped sushi" used herein means small oval-shaped vinegared rice balls topped with sliced fillet of a variety of fish and shellfish, mostly raw but sometimes cooked, or a small slice omelet. The sushi is eaten dipped in soy source, and is food peculiar to Japan but now spreads abroad in the world. Whereas, the term "rice ball" used herein means rice food formed into a round or triangular shape and covered with a dried seaweed-layer sheet, sprinkled with sesame seeds or the like, with the center often filled with pickled plum, codfish roe, salty salmon or spicy boiled foods. This is a popular rice food in Japan for picnics or traveling and called "o-nigiri" or "o-musubi".
A typical conventional food shaping apparatus, particularly, oval-shaped sushi shaping apparatus is disclosed in Japanese Patent Publication No. 38175/1981. The apparatus disclosed was developed by the inventor. The conventional apparatus is adapted to successively form oval-shaped sushi, and comprises a hopper to be charged with boiled rice, a means for dividing the rice to form a plurality of rice blocks of a fixed quantity which is connected to the hopper, a turntable having a plurality of forming cylinders arranged at the periphery thereof which are positioned below the dividing means so as to receive therein the rice block dropped from the dividing means, a piston slidably fitted in each of the cylinders, a pressing means for compressingly forming the rice block into an oval shape in the cylinder in cooperation with the piston, and a driving mechanism for intermittently rotating the turntable.
The dividing means of the conventional apparatus comprises two discs arranged to be vertically spaced from each other and rotate in the same direction which respectively have through-holes formed so as not to be vertically aligned with each other. Accordingly, the apparatus cannot substantially divide boiled rice to form rice blocks of a fixed quantity when the rice has a high viscosity, because the dividing means cannot sufficiently compress the rice. Also, the apparatus does not allow the so-formed rice blocks to be dropped in a constant direction because the discs cut the rice while rotating in the same direction, thus, it is substantially impossible to precisely receive the rice blocks in the forming cylinders.
In the conventional apparatus, boiled rice charged in the hopper is transferred therefrom to the dividing means by means of a transfer means which comprises a pair of endless belts vertically arranged to be opposite to each other at intervals. The endless belt must be formed to have a non-adherent surface or subjected to a surface treatment so that boiled rice does not adhere to the belt. However, it has been found that this does not allow the transfer means to constantly carry the boiled rice because the belt often idles with respect to the rice due to its non-adherent surface. Also, it is required to arrange the belts in a manner to render the lower portion of a gap therebetween narrower. Otherwise, the boiled rice would drop by gravity irrespective of action of the belts. However, this causes a large pressure to be applied to the rice, to thereby interfere with subsequent operations and cause finished oval-shaped sushi to be inferior in aesthetics and taste.
Also, in the conventional apparatus, the pressing means acts to vertically press the rice blocks during rotation of the turntable; thus, it is necessarily required to provide the pressing means with a rotation mechanism, resulting in the apparatus to be complicated in structure. In addition, the conventional pressing means has further disadvantages that an ingredient such as sliced fillet of fish or shellfish put on the rice block is often taken off and it is substantially difficult to control a pressure to be applied onto the rice block.
Further, the conventional apparatus is not provided with a means for applying a Japanese horseradish (wasabi) to the top of the rice block before the ingredient is put on the rice block. This causes such operation to be carried out by hand.
Furthermore, in the conventional apparatus the forming cylinder is formed integral with the turntable. Thus, when oval-shaped sushi is desired which is different in size and/or configuration, it is necessary to exchange the turntable itself, to thereby require much time and labor. Also, cleaning of the cylinder after the preparation of sushi requires removal of the turntable.
Still further, the conventional shaping apparatus has a further disadvantage that a mechanism for controlling the linked actions among the transferring means, dividing means and turntable is not adapted to allow such actions to be controlled as desired. For example, the mechanism often causes malfunction in the operation of shaping rice blocks, resulting in uneven finished sushi being formed. Particularly, the apparatus has a fault in the operation of precisely actuating the transfer means and the turntable or forming means corresponding to the change of operating position of the dividing means.